1. Field of the Invention
The present invention relates generally to a power distributing apparatus and more particularly to such an apparatus for vehicles.
2. Description of the Prior Art
A conventional power distributing apparatus, such as that employing a differential apparatus of first and second output shafts, is constituted by a simple planetary gear which is also utilized for an over-drive apparatus of first output shaft so as to improve a high speed running efficiency, a silent efficiency and a fuel expenses efficiency for vehicles, an input shaft and a carrier of simple planetary gear, a ring gear of simple planetary gear and the first output shaft, and a sun gear of simple planetary gear and the second output shaft are capable of selectively cooperating with each other, and when only the first output shaft is driven the sun gear of simple planetary gear is fixed to a case. When there is no changing between the input shaft and the carrier, the ring gear and the first output shaft, and the sun gear and the second output shaft by various factors in this apparatus, both of torque distributing ratio and over-drive ratio are determined by a ratio of gear number. For example, supposing that the gear number of ring gear is 65 and the gear number of sun gear is 35, the torque distributing ratio (torque of the second output shaft/torque of the first output shaft) becomes 35/65 and the over-drive ratio (rotational number of the input shaft/rotational number of the first output shaft) becomes 0.65. However, it is desirous that the torque distributing ratio responds to a load distributing ratio of each vehicle shaft and it is generally 30-50/70-50 while the over-drive ratio is determined on the basis of the relation between engine output and load and is generally 0.8. Accordingly, both the torque distributing ratio and the over-drive ratio are not capable of adjusting to an appropriate value.